Cardboard box



y 1955 K. R. PERSSON 3,182,886

CARDBOARD BOX Filed Feb. 11, 1963 INVENTOR. a,rL Rune Persson BY 1 4 SL, P

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United States Patent 1,628/ 62 2 Claims. (Cl. 229-34-) This invention relates to a cardboard box comprising double-walled long sides and short sides in the form of hollow members rectangular in cross-section which members at the lower edges of their inner Walls have extensions in the form of wing parts, the wing parts of the long sides being pasted to the bottom of the box and the inner walls of the long sides having near each end a preferably vertical slit through which there is inserted a locking flap forming an extension of the end of the inner wall of the adjacent short side.

The main object of the invention is to provide a box of the type referred to which is suitable for erection by machine.

To attain this object the box according to the invention is characterized in that the lower end of the slit extends slightly inwards into the wing part of the long side and that the portion of the inner wall of the long side that is located between the slit and the end of the long side is bent up, at the place where it meets the Wing part, about a fold line located somewhat further inwards on the wing part than the fold line between the wing part and the inner wall of the long side between the slits such that the edges of each slit are located laterally of each other for forming an opening for the locking flap. Consequently, the slit will be opened when the long sides are erected from a horizontal to an upright position. This opened slit forms a slip-in opening through which the corresponding locking flap of the short side can be conveniently inserted by means of mechanical members.

A suitable embodiment of a blank and a box according to the invention made from this blank is exemplified in the annexed drawing.

FIG. 1 is a top view of the blank according to the invention with one long side turned inwards and with the wing part of this long side pasted to the bottom of the box. FIG. 2 is a diagrammatic perspective view of a corner portion with the illustrated long side in upright position. FIG. 3 is a diagrammatic perspective view of the same corner portion viewed from the opposite direction as compared with FIG. 2 for illustrating the opening formed by the slit and serving for the insertion of the locking flap of the short side. FIG. 4 is a top View of the same corner portion in the erected position of the box and with the long sides connected with the short sides. FIG. 5 is a sectional view of the erected box, the section being taken along a plane parallel to the bottom and located substantially midway of the height of the box. Since all of the corners of the box are devised in the same manner, one corner only is illustrated for the sake of simplicity.

Referring to FIG. 1 the blank for the box is by means of fold lines divided into areas adapted to form the bottom 1, the long sides and the short sides of the box. Each long side comprises an outer wall 2, a top wall 3, an inner wall 4 and a wing part 5. Each short side comice prises an outer wall 6, a top wall 7, an inner Wall 8 and a wing part 9.

The Wing parts 5 of the long sides are coated with an adhesive 10 for pasting the Wing parts to the bottom 1 as shown in the upper part of FIG. 1.

Near the ends of the long sides the inner walls of the long sides have transverse slits 11 which extend vertically in the erected position of the box (FIG. 2.)

As will be seen from FIG. 1, the fold lines 12, 13 extend without interruption as far as to the slits 11 to permit bending of the inner wall 4 of the long side relative to the top wall 3 and bending the wing part 5 away from the inner wall 4.

However, at the slits 11 the fold lines 12, 13 are interrupted such that their ends 12a and 13a located outside the slits are slightly translated toward the wing part 5 as shown in FIGS. 1, 2 and 3. As a result there is obtained a portion 14 located between the fold lines 12a, 13a and the slit 11 and having a transverse fold line 15 which forms the end edge of the long side. Beyond the lastnarned fold line each end of the long sides has an extension in the form of an end flap 16 the base of which extends throughout the height of the portion 14.

Between the outer walls 2 and 6, respectively, of the long sides and the short sides there is provided a corner part 17 adapted to be doubled up.

The ends of the inner walls 8 of the short sides have extensions in the form of locking flaps 2i) adapted to be turned inwards about fold lines 19.

In order to lock the short sides in the erected position of the box, the ends of the wing parts 5 of the long sides have recesses which are open toward the short sides and have each a transverse edge 21 adapted to engage the corresponding wing part of the short sides. These wing parts are adapted to enter the corresponding recesses at the ends of the box and are dimensioned such that the front edges of the wing parts 9 abut upon the edges 21 of the recesses whereby to lock the short sides in their upright positions, as shown in FIGS. 4 and 5.

The end edges of the wing parts 9 are fixed laterally by the longitudinally extending edges 22 of the recesses.

After both long sides have been pasted to the bottom in the manner shown in the upper part of FIG. 1, the blank can be erected by bending both long sides up to the position shown in FIGS. 2 and 3. During this step of operation an opening 23 is formed at each slit 11 as a result of the lateral displacement of the fold lines 12a, 13a relative to the fold lines 12, 13. When the flap 16 is then turned inwards to the position shown in FIG. 5 the portion 14 will be somewhat turned as indicated in FIG. 5 by a slightly oblique position of the portion 14 relative to the inner wall 4, resulting in that the opening 23 will be somewhat enlarged so as still more to facilitate insertion therethrough of the locking flap 29 when the short side is turned inwards. During erection of the short sides from the position shown in FIGS. 2 and 3 the locking flaps 20 are turned up to a position substantially at right angles to the inner walls 8 so that the locking flaps will be able to pass down between the inner Walls of the long sides and along these walls further to the openings 23 and into these openings. The locking flaps 20 are long enough to extend as far as to the end flaps 16 and abut upon these flaps substantially midway thereof, as shown in FIG. 5.

What is claimed is:

1. A carton box made from a single blank having fold lines to form a rectangular bottom and four sides, two opposite sides having upstanding parallel inner and outer longitudinal walls spaced from each other and interconnected by a top wall, said inner end walls being at their ends extended with locking flaps projecting into openings formed by slits in the adjacent inner longitudinal wall,

D said slits extending between the lower and the upper fold lines of each longitudinal wall and dividing the same into 10 inner end edge of said end portion and the adjacent end 15 edge of said intermediate portion.

2. A carton box as defined in claim 1, in which said locking flap has substantially the same width as said inner end wall and said inner longitudinal wall.

References Cited by the Examiner UNITED STATES PATENTS 2,03 8,845 4/36 Locke 22934 X 2,116,513 5/38 Frankenstein 22934 2,860,823 11/58 Frankenstein 2293l FOREIGN PATENTS 222,5 66 7/ 62 Austria.

GEORGE O. RALSTON, Primary Examiner. 

1. A CARTON BOX MADE FROM A SINGLE BLANK HAVING FOLD LINES A FORM A RECTANGULAR BOTTOM AND FOUR SIDES, TWO OPPOSITE SIDES HAVING UPSTANDING PARALLEL INNER AND OUTER LONGITUDINAL WALLS SPACED FROM EACH OTHER AND INTERCONNECTED BY A TOP WALL, SAID INNER END WALLS BEING AT THEIR ENDS EXTENDED WITH LOCKING FLAPS PROJECTING INTO OPENINGS FORMED BY SLITS IN THE ADJACENT INNER LONGITUDINAL WALL, SAID SLITS EXTENDING BETWEEN THE LOWER AND THE UPPER FOLD LINES OF EACH LONGITUDINAL WALL AND DIVIDING THE SAME INTO AT INTERMEDIATE PORTION AND TWO END PORTION, THE UPPER AND THE LOWER FOLD LINES OF SAID END PORTIONS BEING OFFSET INWARDLY RELATIVE TO THE CORRESPONDING FOLD LINES OF SAID INTERMEDIATE PORTION TO FORM SAID OPENING BETWEEN THE INNER END EDGE OF SAID END PORTION AND THE ADJACENT END EDGE OF SAID INTERMEDIATE PORTION. 